The effect of the oral administration of various antigens on the ocular immune response has been tested in the animal model for severe intraocular inflammatory disease, experimental autoimmune uveioretinitis, which is induced by both retinal S-antigen (S-Ag) and interphotoreceptor retinoid- binding protein (IRBP). Oral tolerance could be induced by repeatedly feeding rats with S-Ag. A putative suppresser cell that was CD8 positive could be isolated from the spleen of such animals and transferred to other animals to induce a similar toleragenic effect. In addition, the role of t spleen was confirmed in ongoing animal experiments. A randomized masked trial to evaluate the usefulness of S-Ag feeding in patients with intraocul inflammatory diseases continues. A pilot study was performed in two patients that showed the induction of such tolerance, and these patients continue to be followed.